Analyze my dyno numbers please ... looooooooong
11-11-2002, 06:05 PM
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Location: Charleston, WV, U.S.
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Analyze my dyno numbers please ... looooooooong
Posted in the FI forum and pasted here. Administrators: remove if it's taking too much room but please leave in FI...thanks:
Just have a little time to kill and looking over my dyno graph and table. I'm going to make two different charts here.....one is with the cutout open and is what the car is really tuned for. The other is with the cutout closed so of course it's a little rich on the closed run since it's tuned for a safe A/F when opened. I actually lost power from the cutout because of the A/F having to be tuned rich to compensate for it. It made almost 385 RWHP with the cutout closed on an A/F that was .1 ~ .2 leaner....and could have been turned another .3 leaner or so had the cutout not been a factor.
Numbers with E-valve (cutout) open and closed (all numbers corrected on 248C Dynojet):
OPEN ....................CLOSED........................ ..................
4,900 364.6 .......... 4,900 361.8............................................. ..........
5,000 369.8 .......... 5,000 365.9............................................. ..........
5,100 371.2 .......... 5,100 359.5............................................. ..........
5,200 372.5 .......... 5,200 368.4............................................. ..........
5,300 374.1 .......... 5,300 370.8............................................. ..........
5,400 375.0 .......... 5,400 372.5............................................. ..........
5,500 377.4 .......... 5,500 378.7............................................. ..........
5,600 377.7 .......... 5,600 376.0............................................. ..........
5,700 369.0 .......... 5,700 369.7............................................. ..........
5,800 n/a ...............5,800 368.2............................................. ......
The tuner says the power curve is smoother in the open run because of the leaner A/F that it's tuned on. The closed run richened it up a bit and made it more rough at the upper end. Notice the way the HP is actually more at 4,900 than it is at 5,100 on the closed run? (he says it the richness on the closed run causing it) The actual power peak which isn't displayed in this table is 383.8 (OPEN) ......380.1 (CLOSED). I'm guessing it's at about 5,550 RPM by looking at the graph. Some other interesting things. At 5,000 RPM (OPEN) it's making about 370 RWHP & 5.7 PSI boost .....then at 5,500 RPM it's only making 379 despite a boost level of 6.8 PSI. So a little more than 1.0 PSI only gave me an increase of 9 RWHP going from 5,000 to 5,500 RPM. Yet another weird thing....at 5,700 it's making .7 more HP with exhuast closed.... ??? Also, a peak of 5,550 seems a little low of an RPM for peak power in a centrifugal setup with headers. I have hooker LT's, and 1.6 RR's which you would think would help the topend if anything. Could my intake/heads just be a little more restrictive than average? The tuner said it's not uncommon for supercharged-stock LT1's to start losing power above 5,500 due to intake manifold restriction. Another interesting point of comparison is the 6 PSI '97 Vortech Z28 (also M6) that Morgan Motorsports dyno tuned. It was all stock except for a catback and made 390 RWHP at 5,700 RPM. Yet it made only 350 RWHP at 5,000 RPM. .....so mine makes 20 more RWHP at 5,000 RPM yet makes about 7 ~ 8 less peak than that one. At 5,700 mine is making about 20 less RWHP than that one ......WTF? This car from Morgan Motorsports also had just a hair more low end from like 2,500 to 3,500 (like 5 lbs) ....however, mine has a lot more midrange torque and HP from about 4,000 to 5,500....which is the sweet spot on a stock cammed LT1. There are factors I don't know about the MM car though. Perhaps it was a Mustang dyno and the numbers were uncorrected. It shows that car making 350 RWTQ at 2,500 RPM ......I find that hard to believe. You're telling me a 6 PSI blower and a catback can increase rear wheel torque by 75 ft/lbs at 2,500 RPM? (stock RWTQ at 2,500 is about 275). So how does a catback and maybe 1.5 PSI make 75 RWTQ at 2,500? ....I kinda don't believe it, sorry. Plus, how many stock manifold (all stock except catback) 6 PSI non intercooled LT1's are going to hit 390 RWHP? BTW my uncorrected numbers were 391.1 RWHP and 409.6 RWTQ in about 60 degree weather.....exhaust open run.....so I can make a lot more power in the upcoming months.
Some other interesting things I'd like for some of you to compare to your own dyno sheets: My average RWTQ from 2,200 to 5,700 RPM is 373.4. Average RWHP is 282.5 in that same RPM range. My torque is 345 even down at 2,200 RPM. That brings an interesting point to mind as well. On the exhast open run look at the torque numbers down low:
2,200 345.3
2,300 337.1
2,400 340.2
2,500 346.8
On the closed run it looks like this:
2,200 n/a
2,300 327.9
2,400 336.4
2,500 341.1
Just think it's odd how it has more at 2,200 than it does at 2,300 and 2,400 on the open run. Burst knock? That could have caused my dip in power at 5,100 RPM on the closed run too. His software recorded 0 degrees of knock retard on the open and closed runs.....but it does not record burst knock, and he left the programming in it for burst knock. I think I'm going to disable the burst knock because I'd rather know for sure that the knock retard I see on the Scanmaster is either true or false knock and that there's a problem that needs fixed. (the Scanmaster does report burst knock) I might just start assuming "oh it's just burst knock" every time I see it, not a good ideal.....know what I mean? He said he leaves the burst knock tuned in as a safeguard. I don't think you should need it if you're tuned safe.....there are quirky parameters (sudden changes in airflow on a timer) that have to exist for the burst knock to kick in anyway. BTW my max RWTQ is 401.9 @ 4,550 RPM.
So what do you all think......is mine sort of a dud above 5,000 RPM (especially above 5,500) or what? Sort of seems like it compared to the really strong numbers from 4,500 to 5,000 RPM.
One thing that worries me is trying to read the A/F printout he gave me.....actually, looking at it it looks leaner than what he told me when we were discussing how it had to be adjusted for the cutout. From 3K to 5K it's nice and safe looking at about 12.3 or so overall. Then at about 5,300 it's going gradually leaner as it climbs ....from about 5,500 to 5,700 it looks like the two lines (left side and right side) average out to about 12.7:1. One side is quite a bit leaner than the other and appears to go leaner as the other side goes richer at the end right as he lets his foot off the gas I guess) I asked him if that was safe and he said yes....that actually at that high of an RPM you don't need it quite as rich because there's less load on the motor. That and the timing is at about 26 degrees at 5,700. He says above the power peak he adds lots of fuel and takes the timing way out....to like 15 degrees at 5,900 and then even less as you go up so it sort of acts like a rev limiter. At 6K and up he said there is tons of fuel and hardly any spark to just make it pretty much gradually fall on it's face if you rev it past 6K.
To summarize this "essay".....I want your opinions on the waviness of the power on the closed run up high in the RPM's (the dip at 5,100 more specifically). ....and the open exhaust torque (bog?) at 2,300 and 2,400 RPM. Also, do you think it's kind of a dog above 5,000 (especially above 5,500) for a centrifugal setup with headers? Do you think I should tune out the burst knock with LT1 Edit or maybe send him the computer to tune it out......or is it really a good safeguard to leave in? Like I said I think I'd like it removed so I know I'm either seeing true or false knock from the Scanmaster and know I need to fix something. The only time it hits is here and there (certain parameters) if you're in a given gear just cruising along and suddenly hit it (sudden change in airflow). It's programmed to kick in some retard when this happens at times....it's not really knock retard but still shows on the Scanmater as retard and you don't know if it's from knock, false knock, or burst knock. From 5,500 to 5,800 RPM the A/F graph shows about .4 difference from the left side to the right side and is kind of lean like I said....averaging out to 12.7 or so. This difference in left and right A/F is more apparent when the cutout's closed....it looks to be as much as .6 difference at 5,700 RPM on the exhaust closed run. Looks like about 12.85:1 on one side and 12.3:1 on the other. These are wideband readings and these A/F's are on about 7.3 PSI at that RPM.....just seems a little lean to be real safe to me from what I'm looking at and what I've learned. One more interesting point. The boost spikes from 7.0 PSI to 7.9 PSI from about 5,650 tp 5,800 RPM ...it is a spike compared to the rest of the graph. Could intake/head restriction cause a spike like that in only 150 RPM? (was that a summary )
What do you think of the numbers overall.....should I be happy with the numbers I have with my mods? (8.0 PSI at the max ....say maybe 5,900 ~ 6,000 RPM it should make 8.0, long tubes, !cat, 1.6 RR's, Borla catback). Are my numbers above 5.5K way too low compared to the numbers from 4.5K to 5.5K or what? I will say, this thing pulls great at the low end and mid range......I haven't run it much at the top yet but it it seemed like it at least wasn't a slouch the only two times I took it that high. Should I be happy with the power level for the mods I have? Any advice or opinions welcome...sorry if I repeat myself too much via rewording things I've already said, just want several questions answered/evaluated. Thanks.
Just have a little time to kill and looking over my dyno graph and table. I'm going to make two different charts here.....one is with the cutout open and is what the car is really tuned for. The other is with the cutout closed so of course it's a little rich on the closed run since it's tuned for a safe A/F when opened. I actually lost power from the cutout because of the A/F having to be tuned rich to compensate for it. It made almost 385 RWHP with the cutout closed on an A/F that was .1 ~ .2 leaner....and could have been turned another .3 leaner or so had the cutout not been a factor.
Numbers with E-valve (cutout) open and closed (all numbers corrected on 248C Dynojet):
OPEN ....................CLOSED........................ ..................
4,900 364.6 .......... 4,900 361.8............................................. ..........
5,000 369.8 .......... 5,000 365.9............................................. ..........
5,100 371.2 .......... 5,100 359.5............................................. ..........
5,200 372.5 .......... 5,200 368.4............................................. ..........
5,300 374.1 .......... 5,300 370.8............................................. ..........
5,400 375.0 .......... 5,400 372.5............................................. ..........
5,500 377.4 .......... 5,500 378.7............................................. ..........
5,600 377.7 .......... 5,600 376.0............................................. ..........
5,700 369.0 .......... 5,700 369.7............................................. ..........
5,800 n/a ...............5,800 368.2............................................. ......
The tuner says the power curve is smoother in the open run because of the leaner A/F that it's tuned on. The closed run richened it up a bit and made it more rough at the upper end. Notice the way the HP is actually more at 4,900 than it is at 5,100 on the closed run? (he says it the richness on the closed run causing it) The actual power peak which isn't displayed in this table is 383.8 (OPEN) ......380.1 (CLOSED). I'm guessing it's at about 5,550 RPM by looking at the graph. Some other interesting things. At 5,000 RPM (OPEN) it's making about 370 RWHP & 5.7 PSI boost .....then at 5,500 RPM it's only making 379 despite a boost level of 6.8 PSI. So a little more than 1.0 PSI only gave me an increase of 9 RWHP going from 5,000 to 5,500 RPM. Yet another weird thing....at 5,700 it's making .7 more HP with exhuast closed.... ??? Also, a peak of 5,550 seems a little low of an RPM for peak power in a centrifugal setup with headers. I have hooker LT's, and 1.6 RR's which you would think would help the topend if anything. Could my intake/heads just be a little more restrictive than average? The tuner said it's not uncommon for supercharged-stock LT1's to start losing power above 5,500 due to intake manifold restriction. Another interesting point of comparison is the 6 PSI '97 Vortech Z28 (also M6) that Morgan Motorsports dyno tuned. It was all stock except for a catback and made 390 RWHP at 5,700 RPM. Yet it made only 350 RWHP at 5,000 RPM. .....so mine makes 20 more RWHP at 5,000 RPM yet makes about 7 ~ 8 less peak than that one. At 5,700 mine is making about 20 less RWHP than that one ......WTF? This car from Morgan Motorsports also had just a hair more low end from like 2,500 to 3,500 (like 5 lbs) ....however, mine has a lot more midrange torque and HP from about 4,000 to 5,500....which is the sweet spot on a stock cammed LT1. There are factors I don't know about the MM car though. Perhaps it was a Mustang dyno and the numbers were uncorrected. It shows that car making 350 RWTQ at 2,500 RPM ......I find that hard to believe. You're telling me a 6 PSI blower and a catback can increase rear wheel torque by 75 ft/lbs at 2,500 RPM? (stock RWTQ at 2,500 is about 275). So how does a catback and maybe 1.5 PSI make 75 RWTQ at 2,500? ....I kinda don't believe it, sorry. Plus, how many stock manifold (all stock except catback) 6 PSI non intercooled LT1's are going to hit 390 RWHP? BTW my uncorrected numbers were 391.1 RWHP and 409.6 RWTQ in about 60 degree weather.....exhaust open run.....so I can make a lot more power in the upcoming months.
Some other interesting things I'd like for some of you to compare to your own dyno sheets: My average RWTQ from 2,200 to 5,700 RPM is 373.4. Average RWHP is 282.5 in that same RPM range. My torque is 345 even down at 2,200 RPM. That brings an interesting point to mind as well. On the exhast open run look at the torque numbers down low:
2,200 345.3
2,300 337.1
2,400 340.2
2,500 346.8
On the closed run it looks like this:
2,200 n/a
2,300 327.9
2,400 336.4
2,500 341.1
Just think it's odd how it has more at 2,200 than it does at 2,300 and 2,400 on the open run. Burst knock? That could have caused my dip in power at 5,100 RPM on the closed run too. His software recorded 0 degrees of knock retard on the open and closed runs.....but it does not record burst knock, and he left the programming in it for burst knock. I think I'm going to disable the burst knock because I'd rather know for sure that the knock retard I see on the Scanmaster is either true or false knock and that there's a problem that needs fixed. (the Scanmaster does report burst knock) I might just start assuming "oh it's just burst knock" every time I see it, not a good ideal.....know what I mean? He said he leaves the burst knock tuned in as a safeguard. I don't think you should need it if you're tuned safe.....there are quirky parameters (sudden changes in airflow on a timer) that have to exist for the burst knock to kick in anyway. BTW my max RWTQ is 401.9 @ 4,550 RPM.
So what do you all think......is mine sort of a dud above 5,000 RPM (especially above 5,500) or what? Sort of seems like it compared to the really strong numbers from 4,500 to 5,000 RPM.
One thing that worries me is trying to read the A/F printout he gave me.....actually, looking at it it looks leaner than what he told me when we were discussing how it had to be adjusted for the cutout. From 3K to 5K it's nice and safe looking at about 12.3 or so overall. Then at about 5,300 it's going gradually leaner as it climbs ....from about 5,500 to 5,700 it looks like the two lines (left side and right side) average out to about 12.7:1. One side is quite a bit leaner than the other and appears to go leaner as the other side goes richer at the end right as he lets his foot off the gas I guess) I asked him if that was safe and he said yes....that actually at that high of an RPM you don't need it quite as rich because there's less load on the motor. That and the timing is at about 26 degrees at 5,700. He says above the power peak he adds lots of fuel and takes the timing way out....to like 15 degrees at 5,900 and then even less as you go up so it sort of acts like a rev limiter. At 6K and up he said there is tons of fuel and hardly any spark to just make it pretty much gradually fall on it's face if you rev it past 6K.
To summarize this "essay".....I want your opinions on the waviness of the power on the closed run up high in the RPM's (the dip at 5,100 more specifically). ....and the open exhaust torque (bog?) at 2,300 and 2,400 RPM. Also, do you think it's kind of a dog above 5,000 (especially above 5,500) for a centrifugal setup with headers? Do you think I should tune out the burst knock with LT1 Edit or maybe send him the computer to tune it out......or is it really a good safeguard to leave in? Like I said I think I'd like it removed so I know I'm either seeing true or false knock from the Scanmaster and know I need to fix something. The only time it hits is here and there (certain parameters) if you're in a given gear just cruising along and suddenly hit it (sudden change in airflow). It's programmed to kick in some retard when this happens at times....it's not really knock retard but still shows on the Scanmater as retard and you don't know if it's from knock, false knock, or burst knock. From 5,500 to 5,800 RPM the A/F graph shows about .4 difference from the left side to the right side and is kind of lean like I said....averaging out to 12.7 or so. This difference in left and right A/F is more apparent when the cutout's closed....it looks to be as much as .6 difference at 5,700 RPM on the exhaust closed run. Looks like about 12.85:1 on one side and 12.3:1 on the other. These are wideband readings and these A/F's are on about 7.3 PSI at that RPM.....just seems a little lean to be real safe to me from what I'm looking at and what I've learned. One more interesting point. The boost spikes from 7.0 PSI to 7.9 PSI from about 5,650 tp 5,800 RPM ...it is a spike compared to the rest of the graph. Could intake/head restriction cause a spike like that in only 150 RPM? (was that a summary )
What do you think of the numbers overall.....should I be happy with the numbers I have with my mods? (8.0 PSI at the max ....say maybe 5,900 ~ 6,000 RPM it should make 8.0, long tubes, !cat, 1.6 RR's, Borla catback). Are my numbers above 5.5K way too low compared to the numbers from 4.5K to 5.5K or what? I will say, this thing pulls great at the low end and mid range......I haven't run it much at the top yet but it it seemed like it at least wasn't a slouch the only two times I took it that high. Should I be happy with the power level for the mods I have? Any advice or opinions welcome...sorry if I repeat myself too much via rewording things I've already said, just want several questions answered/evaluated. Thanks.
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